They should be taken away from minors in general. No smart phone before 18. Ideally, nobody should ever have a smart phone. The best time to implement any strategy for limiting smart phone use was 8 to 10 years ago, when the addictive effects were obvious. The second best time is right now.
Nobody should have a smartphone? I know a lot of very interesting takes come up when the smartphones/kids debate comes up, but this comment certainly takes the cake.